Coffee Cutoff Time by Bedtime: Your Latest Safe Cup

Your coffee cutoff is the latest time you can finish a cup and still fall under ~50 mg of caffeine at bedtime — the level where sleep starts to suffer. For one regular cup (95 mg), that's roughly 7–8 hours before bed; for two cups (~200 mg), about 5 hours earlier still. Below are exact cutoffs for 9, 10, 11 PM and midnight bedtimes.

Why there's a cutoff at all

Caffeine doesn't leave your body the moment you feel the buzz fade. It clears on a steady curve with a half-life of about 5 hours — every 5 hours, the amount in your system roughly halves. So a coffee finished at 3 PM is still meaningfully present at 10 PM.

Sleep researchers find that most people sleep best with less than about 50 mg of caffeine on board at bedtime. In a controlled 2013 study by Drake and colleagues, even a dose taken a full 6 hours before bed measurably cut total sleep time — proof that the problem isn't whether you feel wired, but how much caffeine is still circulating. The cutoff is simply the clock time that keeps your bedtime number under 50 mg.

The half-life math, in plain English

The whole thing runs on one formula:

Caffeine remaining = dose × 0.5 ^ (hours ÷ 5)

If you drink 95 mg and 5 hours pass, you have 95 × 0.5 = ~47 mg left. After 10 hours, half again: ~24 mg. To find a cutoff, flip it around: solve for the number of hours it takes to fall below 50 mg, then count back from when you want to be asleep.

• A 95 mg cup drops under 50 mg after about 4.6 hours.
• A 200 mg dose (two cups) drops under 50 mg after about 10 hours.

That gap is why dose matters more than people think — doubling the coffee more than doubles the wait.

👉 Don't want to do the algebra? Try the calculator and get your exact cutoff for your bedtime, drink size and metabolism in one tap.

Coffee cutoff time by bedtime (1 cup, ~95 mg)

A single regular brewed coffee runs about 95 mg, per USDA caffeine data. Here's the latest time to finish one so you're under ~50 mg when your head hits the pillow:

A single cup is forgiving — even a late-afternoon coffee usually clears in time for an average bedtime.

Coffee cutoff time by bedtime (2 cups, ~200 mg)

Two cups, a large drip, or a strong mug pushes the math hard. Now you need about 10 hours to fall under 50 mg:

This is the version that surprises people: with a 200 mg habit, your real cutoff is often lunchtime, not the afternoon. If you regularly drink two cups together, treat noon as your last call.

Three things that shift your personal cutoff

These tables use population averages. Three factors move your real number — sometimes by hours.

1. Body weight and dose-per-kilogram

Caffeine's effect scales with body size. The FDA notes adults can generally tolerate up to about 200 mg in a single dose and 400 mg across a day, but a lighter person reaches a given blood level on less caffeine. If you're smaller than average, treat the 200 mg tables as your default even for what looks like a moderate cup.

2. Sensitivity at bedtime

The ~50 mg threshold is a useful average, not a hard wall. Some sleepers notice fragmented or shallow sleep below it; others tolerate a bit more. If you fall asleep fine but wake unrefreshed, your personal threshold may be lower — move your cutoff earlier and watch what changes.

3. Your metabolism (CYP1A2)

This is the biggest lever. Caffeine half-life ranges from about 3 hours in fast metabolizers to 9+ hours in slow ones, driven largely by the CYP1A2 liver-enzyme gene. A slow metabolizer on a 9-hour half-life needs roughly double the clearance time of the tables above. Smoking speeds caffeine clearance; pregnancy, oral contraceptives and older age slow it. If coffee lingers or "hits hard," assume you're on the slow end and move your cutoff earlier. (See Are you a fast or slow caffeine metabolizer?.)

A worked example: the 11 PM sleeper who can't unwind

Say you go to bed at 11 PM and grab a 200 mg "afternoon pick-me-up" at 4 PM. From the formula, that's 7 hours of clearance by bedtime: 200 × 0.5^(7÷5) = ~76 mg still on board. That's well above the 50 mg line — enough to lengthen the time it takes to fall asleep and to shave deep sleep off the front of the night, even if you don't feel "wired." Move that same drink to 1 PM and you get 10 hours of clearance, landing right at ~50 mg by bedtime — the difference between a restless night and a normal one, from nothing but a three-hour shift.

Now run it as a slow metabolizer with a 9-hour half-life: that 4 PM, 200 mg drink leaves 200 × 0.5^(7÷9) = ~117 mg at 11 PM — more than double the threshold. Same coffee, same clock, completely different night. This is why a single published "cutoff time" can't fit everyone; the cutoff is personal arithmetic, not a universal rule.

Common mistakes that blow past your cutoff

• Counting cups, not milligrams. A 16 oz café coffee can carry 250–300 mg — two "cups" by volume, but closer to three by caffeine. Always think in milligrams.
• Forgetting hidden caffeine. Chocolate, some pain relievers, pre-workout, matcha and soda all stack onto your bedtime total. Your cutoff covers total caffeine, not just coffee.
• Trusting the buzz clock. The alert feeling fades in a few hours, so people assume the caffeine is gone. It isn't — clearance runs far longer than the effect, which is exactly why a "harmless" 4 PM cup shows up at midnight.
• Ignoring tolerance vs. clearance. Drinking caffeine daily builds tolerance to the feeling, but it does almost nothing to speed up how fast you clear it. You can stop noticing the buzz and still be over 50 mg at bedtime.

How to use your cutoff in real life

• Pick one last-call time and defend it — say "no coffee after 2 PM." A fixed rule beats willpower every afternoon.
• Front-load your caffeine. Getting most of your intake before lunch gives every dose more half-lives to clear.
• Swap, don't skip. After your cutoff, reach for decaf (~2–5 mg) or herbal tea so the ritual stays without the sleep cost.
• Watch other sources. A pre-workout, a Celsius, or an afternoon soda all eat into the same budget — time them like coffee.
• Recheck the afternoon edge cases. Wondering about that mid-afternoon cup specifically? See is 3 PM too late for coffee?

The bottom line

There's no universal coffee curfew — there's 50 mg at bedtime, and a cutoff is just the clock time that math points to. One cup gives you until late afternoon; two cups often means stopping by noon. Your weight, sensitivity and metabolism can move that by hours, so the only truly accurate cutoff is the one calculated from your drinks against your bedtime.

Stop guessing your last call. The Caffeine & Sleep app logs every drink in one tap, models your personal caffeine curve, and pings you 30 minutes before your cutoff — so you always know your latest safe cup for tonight's bedtime. Get the app →